#!/usr/bin/env python
###############################################################################
#
# Run clang-format on the whole repository
#
# Author: Maxime Arthaud
#
# Contact: ikos@lists.nasa.gov
#
# Notices:
#
# Copyright (c) 2011-2019 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# All Rights Reserved.
#
# Disclaimers:
#
# No Warranty: THE SUBJECT SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY OF
# ANY KIND, EITHER EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING, BUT NOT LIMITED
# TO, ANY WARRANTY THAT THE SUBJECT SOFTWARE WILL CONFORM TO SPECIFICATIONS,
# ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
# OR FREEDOM FROM INFRINGEMENT, ANY WARRANTY THAT THE SUBJECT SOFTWARE WILL BE
# ERROR FREE, OR ANY WARRANTY THAT DOCUMENTATION, IF PROVIDED, WILL CONFORM TO
# THE SUBJECT SOFTWARE. THIS AGREEMENT DOES NOT, IN ANY MANNER, CONSTITUTE AN
# ENDORSEMENT BY GOVERNMENT AGENCY OR ANY PRIOR RECIPIENT OF ANY RESULTS,
# RESULTING DESIGNS, HARDWARE, SOFTWARE PRODUCTS OR ANY OTHER APPLICATIONS
# RESULTING FROM USE OF THE SUBJECT SOFTWARE.  FURTHER, GOVERNMENT AGENCY
# DISCLAIMS ALL WARRANTIES AND LIABILITIES REGARDING THIRD-PARTY SOFTWARE,
# IF PRESENT IN THE ORIGINAL SOFTWARE, AND DISTRIBUTES IT "AS IS."
#
# Waiver and Indemnity:  RECIPIENT AGREES TO WAIVE ANY AND ALL CLAIMS AGAINST
# THE UNITED STATES GOVERNMENT, ITS CONTRACTORS AND SUBCONTRACTORS, AS WELL
# AS ANY PRIOR RECIPIENT.  IF RECIPIENT'S USE OF THE SUBJECT SOFTWARE RESULTS
# IN ANY LIABILITIES, DEMANDS, DAMAGES, EXPENSES OR LOSSES ARISING FROM SUCH
# USE, INCLUDING ANY DAMAGES FROM PRODUCTS BASED ON, OR RESULTING FROM,
# RECIPIENT'S USE OF THE SUBJECT SOFTWARE, RECIPIENT SHALL INDEMNIFY AND HOLD
# HARMLESS THE UNITED STATES GOVERNMENT, ITS CONTRACTORS AND SUBCONTRACTORS,
# AS WELL AS ANY PRIOR RECIPIENT, TO THE EXTENT PERMITTED BY LAW.
# RECIPIENT'S SOLE REMEDY FOR ANY SUCH MATTER SHALL BE THE IMMEDIATE,
# UNILATERAL TERMINATION OF THIS AGREEMENT.
#
###############################################################################
import argparse
import os
import os.path
import re
import subprocess
import sys


# Expected clang-format version
CLANG_FORMAT_VERSION = '9.0.0'

# Extensions to format
SOURCE_EXTENSIONS = ('.c', '.cpp', '.h', '.hpp')

# Directories to ignore
IGNORE_DIRECTORIES = ('.git', 'build')


def printf(fmt, *args, **kwargs):
    file = kwargs.pop('file', sys.stdout)
    file.write(fmt % args if args else fmt)
    file.flush()


def is_executable(fpath):
    return fpath and os.path.isfile(fpath) and os.access(fpath, os.X_OK)


def which(program):
    ''' Try to find program in the PATH, otherwise return None.

    >>> which('cat')
    '/bin/cat'
    '''
    fpath, fname = os.path.split(program)
    if fpath:
        if is_executable(program):
            return program
    else:
        for path in os.environ['PATH'].split(os.pathsep):
            exe_file = os.path.join(path, program)
            if is_executable(exe_file):
                return exe_file

    return None


if __name__ == '__main__':
    progname = os.path.basename(sys.argv[0])

    # Default source directory is the parent directory
    src_dir = os.path.join(os.path.dirname(sys.argv[0]), '..')
    src_dir = os.path.normpath(src_dir)

    # Parse arguments
    description = 'Run clang-format on the whole repository'
    parser = argparse.ArgumentParser(description=description)
    parser.add_argument('--srcdir',
                        dest='src_dir',
                        help='Path to the source directory [%s]' % src_dir,
                        default=src_dir)
    parser.add_argument('--clang-format',
                        dest='clang_format',
                        help='Path to the clang-format binary',
                        default='clang-format')
    opt = parser.parse_args()

    # Check source directory
    if not os.path.isdir(opt.src_dir):
        printf("%s: error: '%s' is not a directory\n",
               progname,
               opt.src_dir,
               file=sys.stderr)
        sys.exit(1)

    # Check clang-format
    clang_format = which(opt.clang_format)
    if not clang_format:
        printf('%s: error: %s: command not found\n',
               progname,
               opt.clang_format,
               file=sys.stderr)
        sys.exit(1)

    # Check clang-format version
    output = subprocess.check_output([clang_format, '--version'])
    output = output.decode('utf-8')
    r = re.match(r'^clang-format version ([0-9\.]+) \(.*\)\s*$', output)
    if not r:
        printf("%s: error: unexpected output of '%s --version'\n",
               progname,
               opt.clang_format,
               file=sys.stderr)
        sys.exit(1)

    version = r.group(1)
    if version != CLANG_FORMAT_VERSION:
        printf("%s: error: trying to use clang-format %s, expecting %s\n",
               progname,
               version,
               CLANG_FORMAT_VERSION,
               file=sys.stderr)
        sys.exit(1)

    os.chdir(opt.src_dir)

    for dirpath, _, filenames in os.walk('.'):
        if dirpath.startswith('./'):
            dirpath = dirpath[2:]

        if any(dirpath.startswith(n) for n in IGNORE_DIRECTORIES):
            continue

        for filename in filenames:
            _, ext = os.path.splitext(filename)

            if ext in SOURCE_EXTENSIONS:
                fullpath = os.path.join(dirpath, filename)
                printf("[*] Formatting %s\n", fullpath)
                subprocess.check_call([clang_format,
                                       '-i',
                                       '-style=file',
                                       fullpath])
